Werner complexes



United States WERNER COMPLEXES No Drawing. Application January 2, 1953 Serial No. 329,434

4 Claims. (Cl. 260-270) This invention relates to a novel class of metal compounds which are highly soluble in hydrocarbon oils and other non-polar solvents. Broadly speaking the new compounds are coordinate complexes of the Werner type wherein the basic nitrogen component is an alkyl-substituted pyridine base containing more than 6 carbon atoms, and the anion consists of three or more atoms so combined as to produce the phenomenon known as resonance stabilization, as e. g. thiocyanate.

The primary object of this invention is to provide means whereby large proportions of metals may be dissolved in non-polar solvents such as hydrocarbon oils, thereby providing stable solutions containing e. g. from to 20% by weight of metal.

Another object is to provide oil-soluble complexes of metal salts and amines wherein the non-metallic constituents are non-corrosive.

Still another object is to provide a broad class of such oil-soluble, non-corrosive complexes which may be rap idly and easily prepared without expensive equipment or procedures.

Other objects will be apparent to those skilled in the art from the description which follows.

There exists in many industrial and chemical fields a need for metal compounds which are highly soluble in non-polar solvents, and which are stable, non-corrosive and cheaply prepared. Examples of such fields include lubricating oils, paints, solvents, thinners, rubber, plastics, insecticides, etc. The metal complexes described herein find use in these various fields, and in other fields, as oxidation. accelerators, polymerization catalysts, anti-corrosive agents, insecticides, fungicides, radioactive tracers, etc.

Hydrocarbon solutions of the appropriate metal complexes may also be employed to impregnate solids with metals. This is particularly desirable when anhydrous impregnation conditions are desired, or when it is desired to impregnate a hydrophobic solid. It is often desired for example to impregnate activated carbon with metal compounds for catalytic purposes, and since that material is ordinarily hydrophobic, aqueous solutions of a metal salt .tend to give uneven or non-intimate deposition of metal. .By impregnating such materials with a hydrocarbon solution of the desired metal complex, and subsequently decomposing the complex e. g. by heating, a very even and intimate distribution of metal is obtained. This procedure may be employed for impregnating other oleophyllic catalytic materials, adsorbents, etc.

V In addition to their valuable properties resulting from oil-solubility, the complexes described herein are also useful in other applications. They may be employed for example to separate diflicultly separable organic compounds e. g. isomers, by selective absorption or clathration as described in the copending application of William D. Schaeffer, Serial No. 274,647, filed March 3, 1952, now abandoned.

The complexes of this invention may be designated broadly as coordinate-bonded reaction products of metal ions, certain basic nitrogen-containing organic compounds and certain anions. They are very easily formed by merely bringing together the stoichiometric ratios of the three components, either in the presence or absence of a solvent. In some cases, though not generally, a gentle heating may be desirable to hasten the reaction. If a solvent is employed, it is preferably water, but other solvents may be employed e. g. methanol, ethanol, isopropanol, ethylene glycol, chloroform, diethyl ether, acetone, etc.

In the preferred method of preparation, a salt of the desired metal ion is first dissolved in water. The anion of this salt should be one which forms a water-soluble complex with the desired amine and metal ion. This means that the anion should not be the same as that desired in the final complex, since the desired complexes are water-insoluble. To the initial solution of metal salt, the required amount of amine is then added and the mixture is stirred until a homogeneous solution is formed. The water soluble complex solution is then mixed with a compound which furnishes the anion desired in the final complex, e. g. thiocyanate, whereupon a water-insoluble complex precipitates out. The precipitate is then recovered, washed and dried to give the desired oilsoluble complex.

The initial salt may be a chloride, bromide, sulfate,

nitrate, phosphate, acetate, or any water-soluble salt which forms water-soluble complexes with the desired amine. This selection is preferable because the amines employed herein are water-insoluble or only slightly soluble, and the formation of the initial soluble complex provides a convenient method for contacting the amine with the precipitating anion.

Suitable complexes as described herein may be prepared embodying generally any metal component having an atomic number of 13 or above. The most readily utilizable metals, and the ones of which oil-soluble compounds are most desired are those of groups L-B, II-B, VIB, VII-B and VIII-B of the periodic table. Chromium, manganese, iron, cobalt, nickel, copper, zinc, molybdenum, silver, cadmium, palladium, tungsten, osmium, iridium, platinum, gold, mercury, and uranium are prime examples. Aluminum, tin, antimony, lead, and bismuth may also be employed.

In order to obtain oil-solubility of the above metals as coordinate complexes it is necessary to select a proper amine and a proper anion. Those amines containing an aromatic ring, i. e. one characterized by the type of bonding leading to resonance stabilization are preferable to non-aromatics for producing highly oil-soluble complexes. It is further preferred that the carbon atoms alpha to at least one hetero-N atom should be unsubstituted, since the alpha substituted amines, e. g. 2,6 lutidine, form complexes only with great difiiculty. Examples of suitable amines include the 3- and 4-alkyl pyridines which contain more than one alkyl carbon atom, in all of which the alkyl substitution is sufiicient to provide a total of more than 6 carbon atoms in the amine. Specific exam ples include:

4-propyl pyridine 4-butyl pyridine 4-ethyl pyridine 3-ethyl pyridine Many other amines falling within the above categories will occur to those skilled in the art.

The preferred anions which are found to give optimum oil-solubility characteristics are those containing at least three atoms which are so bonded as to permit resonance References Cited in the file of this patent UNITED STATES PATENTS 234,772 Stusser Sept. 15, 1936 343,569 Beber Sept. 2, 1947 5 388,374 Long et a1. Mar. 9, 1948 Brauner Apr. 12, 1949 Smith July 19, 1949 Franz May 22, 1951 6 FOREIGN PATENTS Great Britain Mar. 8, 1926 Great Britain Feb. 23, 1931 Great Britain Feb. 20, 1933 OTHER REFERENCES Beilsteins Handbuch der Organischen Chemie Vierte Aufiage, Band XX Seite 236 Verlag, 1935. 

1. A METHOD FOR PREPARING A HYDROCARBON SOLUTION OF A METAL OF ATOMIC NUMBER 25-29 INCLUSIVE WHICH COMPRISES COMPLEXING A SALT OF SAID METAL WITH FOUR MOLEEQUIVALENTS OF AN ALKYL-PYRIDINE BASE TO FORM A TETRACOORDINATED WERNER COMPLEX, THEN DISSOLVING SAID WERNER COMPLEX IN SAID HYDROCARBON OIL, SAID ALKYL PYRIDINE BASE CONTAINING AT LEAST 2 AND NOT MORE THAN 9 ALKYL CARBON ATOMS, ALL OF SAID ALKYL CARBON ATOMS BEING IN THE FORM OF ALKYL GROUPS ATTACHED TO THE RING IN POSITIONS NON-ADJACENT TO THE HETERO-N ATOM. 